1. Field of the Invention
The invention relates to an incoming call alert system for use with cellular telephones. More specifically, the invention relates to such a system which is physically separate from and which is not wired to the cellular telephone in association with which it is used.
2. Description of Prior Art
It is known in the art to provide circuitry or the like for modifying the alert systems (e.g. ringers) of cellular telephones. Examples of such modifications are illustrated in, for example, U.S. Pat. No. 4,076,968, Wattenbarger, Feb. 28, 1978, U.S. Pat. No. 4,214,131, Bush et al, Jul. 22, 1980 and U.S. Pat. No. 5,025,467, Wheller, Jun. 18, 1991. Typically, the cellular telephones have to be opened up to receive the circuitry or to be wired thereto.
Thus, the '968 patent teaches a telephone set which includes circuitry for automatically controlling the intensity of the ringer. The ambient noise is detected by a noise measuring circuit whose output is fed to a control circuit. The ringer intensity is then set by the control circuit. As seen in FIGS. 1 and 2 of the '968 patent, the ringer is physically wired to the transmitter and the receiver and the signals travel along the conductive wiring. Accordingly, the set would have to be opened to install the circuitry.
The purpose of the '131 invention is to provide an electronic circuit to replace electromechanical ringers of a telephone set. The electronic circuit is illustrated in FIG. 5 of the patent. At recited in the abstract, the electronic ringer can be use ". . . either as a replacement for that ringer in existing telephone instruments or as a part of the original manufactured instrument". When used as a replacement it would of course be necessary to open up the telephone set to install the electronic circuitry.
The '467 reference includes a "remote" telephone ringer for use in a cellular telephone in a car. The ringer produces a loud, but pleasant, ring so that the user can be alerted to an incoming call even if he is some distance from the car. However, once again, the ringer is wired to the cellular telephone set. Thus, the wire 80 is connected into the cellular telephone. Accordingly, although the cellular telephone does not have to be opened to install the entire ringing system, it nevertheless does have to be opened for an installation of the ringing system to work with the cellular telephone.
In any case, signals are sent by wire from the cellular telephone to the ringing system.
It is also known that some cellular telephones do suffer from their inability to produce a loud enough audio alert signal, and from their inability to provide a non-audible alert signal when an audible alert signal would be inconvenient.
For example, when travelling in a car with the windows opened and the car radio turned ON, the background noise will typically mask the cellular telephone ringer so that telephone calls could be missed. Also, when attending meetings or when in restaurants, it could be disruptive to receive an audible alert signal so that it would be advantageous to have a non-audible alert signal so that the telephone owner will be alerted about a telephone call without providing any disruption.